1. Field of the Invention
The present invention relates to a method of manufacturing a liquid crystal display device. More particularly, the present invention relates to a method of forming an alignment layer of a liquid crystal display device.
2. Description of the Related Art
In general, an alignment layer of a liquid crystal display (LCD) device is formed by rubbing an organic layer with a rubbing cloth. However, the organic layer directly makes contact with the rubbing cloth to cause static electricity and/or impurities, and the static electricity and/or the impurities causes a malfunction of an electrical circuit and/or deteriorate alignment uniformity. Furthermore, in the rubbing method using a rubbing cloth, adjusting a pretilt angle of a liquid crystal molecule and/or finely arranging alignment is difficult so that there are limits to forming a multi-domain alignment. In order to prevent the above-mentioned problems, a photo-alignment method has been developed. However, stability, such as thermal stability of a photosensitive polymer of the photo-alignment method decreases as time goes by so that reliability of the alignment becomes low. Also, the photo-alignment method needs a light source requiring large amounts of energy. Thus, the photo-alignment method is not practically used.
Recently, active research has been conducted on an ion-beam alignment method, wherein an ion beam is irradiated onto the alignment layer. The ion-beam alignment method has merits, as described below. That is, the ion-beam alignment method may be applied to a conventional organic alignment layer of polyimide, so that a new alignment layer is not required. Furthermore, a pretilt angle of a liquid crystal molecule may be adjusted by an ion beam with low energy. However, the adjustment of a pretilt angle of a liquid crystal molecule is limited to vertical alignment, and successive variations of a pretilt angle are very difficult to perform. Furthermore, the ion-beam alignment method requires a vacuum chamber for generating and irradiating an ion beam.